<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    table {
      /* 取消边框之间的间隙 */
      border-collapse: collapse;
      text-align: center;
    }

    td {
      border: 1px solid red;
      /* 撑大盒子 */
      padding: 10px 20px;
    }
  </style>
</head>
<body>

  <!-- 
    1.确定  "谁"  需要跨行或者跨列
    2.确定是跨"行"还是跨"列"
    3.跨几行或者几列
   -->
  
  <!-- 跨列演练 -->
  <table>
    <tr>
      <td colspan="2">1-1</td>
    </tr>
    <tr>
      <td>2-1</td>
      <td>2-2</td>
    </tr>
  </table>

  <!-- 跨行演练 -->
  <!-- <table>
    <tr>
      <td rowspan="2">1-1</td>
      <td>1-2</td>
    </tr>
    <tr>
      <td>2-2</td>
    </tr>
  </table> -->

</body>
</html>